A transmitter can transmit a signal to a receiver over a communication channel such as a backplane. The signal can encode various data. If the communication channel is not perfect, then the signal received by the receiver may not be identical to the signal transited by the transmitter. For instance, the communication channel may have introduced noise into the signal. If the signal received by the receiver is distorted enough by the communication channel, then the data may not be recoverable by the receiver.
FEC (Forward Error Correction) or channel coding is a technique that involves encoding a signal in a redundant manner so that data sent with the signal may be recoverable even if there are errors in transmission. Such techniques may be employed when it is difficult or impractical to support re-transmission of data following an error. RS (Reed Solomon) encoding is an example FEC. Other FECs exist.